Seal



F. S. EVES I Nov. 7, 1944.

SEAL

Filed April 2, 1945 Patented Nov. 7, 1944 PATENT OFFICE snu. FrederickSydney Eves, Leamington Spa, England,

assignor to Automotive Products Company Limited, Leamington SDI, EnglandApplication April 2', 194:, Serial No. 481,622 In Great Britain January16, 1842 2 Claims. This invention relates to fluid seals for use betweenrelatively rotating members and it has for its primary object to providea simple yet efllcient form of seal. The invention is, of course, ofparticular utility in connection with shafts and like members adapted tohave a rotary or angular movement relative to a housing or equivalent,the

packing being operatively interposed between the shaft and the housingin order to prevent leakage v of fluid into and/or out of said housing.

In a packing device, for preventing leakage of fluid in an axialdirection between a pair of members which move 'angularly one within theother,

comprising an annular sealing member of soft resilient material, such asrubber, the invention is characterised by the fact that retaining means,for clamping the sealing member in -a radial direction into firmengagement with the bottom of a circumferential groove formed in one ofthe relatively movable members, is disposed between said sealing memberand the other of the relatively movable members, the retaining meansleaving an annular portion of the sealing memher free to bear upon thesurface of the said other of the relatively movable members.

There is further provided according to the invention a packing devicefor preventing leakage of fluid in an axial direction between a pair ofmembers arranged to move angularly one within the other, said packingdevice comprising an annular sealing member which is of substantial withthe sealing member, said band conveniently being endless. If desired,the groove which accommodates the sealing member may be formed on theouter surface of the inner of the relatively movable members. Theretaining means can comprise a plurality of turns of wire which maytween the side ofthe groove and the adjacent surface of the sealingmember, "so that the latter tends to become compressed axially and tospread length which is clamped against the bottom of the groove by theretaining means, and the other limb forming a substantially radialflange adapted to extend alongside the retaining means so as to bearagainst the other of said relatively movable members. v

.The invention is illustrated by way of example in the accompanyingdiagrammatic drawing, in

- which: r

1 Figure 1 is an elevation, partly in section, showing an improvedpacking device for a rotary shaft;

Figure 2 is a'fragmentary radial section of the packing corresponding toFigure 1 but drawn to an enlargedscale;

Figures 3 and 4 are also fragmentary radial 26 sections but showingmodified forms of construction;

Figure 5 is a radial section of the retaining means, showing one methodof securing the turns of wire; and

Figure 6 is a sectional elevation showing how .the packing device can beapplied to a housing or other outer member.

s In the general arrangement shown in Figure 1 a housing, casing,partition or other member constituting part of a fluid pressureapparatus is indicated generally at In ind is formed with a bore "itthrough which "passes a shaft H, the latter being arranged to rotateabout its axis, which isindicated in broken lines at l3. It is 40required to prevent leakage of pressure fluid (i. e., gas or liquid,depending upon the apparatus in which the invention is utilised) fromthe space It at one side of the member Hi to the space ii "at the other,or vice versa, and for this purpose the shaft I2 is provided with anannular packing device, which is indicated generally at It in Figure1,'said packing device being accommodated within a circumferentialgroove I! of relatively shallow rectangular cross-section formed aroundthe shaft l2.

The construction of the packing device will be seen more clearly fromFigure 2 and it comprises an annularseallng member l8, which is composedof soft rubber or like readily deformable resilient material, saidsealing member belngof tion, one limb constituting a tube of short axialsubstantially U-shaped radial section so as to fit snugly within thegroove it and virtually constitute a lining therefor. The axial lengthof the sealing member it, when fitted is preferably slightly less thanthe corresponding dimension of the groove ll, as shown in Figure 2,these measurements being indicated at s and G respectively. This leavesat one or each side of the sealing member is a thin annular space to.The limbs or side portions to and 2i of the sealing member iii aresufficiently wide in a radial direction to be an interference fitbetween the bottom 22 of the groove ii in the shaft :12 and the surfaceof the bore ii in the member 36, thus pro viding a seal to preventleakage of fluid between the members iii and 62 in either direction. Theefficiency of this seal is improved by the provision of the space orspaces is, since the fluid under pressure can gain access to this space(or where two such spaces are present, to that space as which is nearerto the pressure fluid being sealed), and by acting upon the adjacentradial surface of the limb 2a or 2i compress said limb in an axialdirection, thereby causing it to tend to spread radially and as a resultto press more firmly upon the surface of the bore 1 i.

- The sealing member it is maintained in firm and uniform grippingengagement with the shaft i2 by retaining means, which is indicated generally at 23, and comprises a plurality of turns of stout metal wirewound in the form of a helix so as to fill substantially the spacebetween the limbs 28 and 2! of the sealing member ill. The turns it arewound relatively tightly upon the intermediate or base portion 25 of thesealing member it, or, if desired, the retaining means 23 may beconstructed from springy wire so that it contracts resiliently of itsown accord so as to force the sealing member is into firm contact withthe bottom 22 of the groove ill. The provision of the retaining meanshas a decidedly beneficial effect in keeping the sealing member l8 inshape and may prevent it from becoming jammed locally (and consequentlystretched at other parts) due to therelatlve rotation between themembers ill and I2. The emciency of the seal is thus preserved when theparts are in motion and its useful life is also increased by theprovision of the retaining means 23.

An alternative construction is shown in Figure 3 and this is primarilyapplicable where the packing device is installed adJacent the end of theshaft F2 or a shoulder formed on said shaft.

The end of the shaft i2 is screw-threaded at 26 for. the reception of acollar 27, which, when in position, forms a removable side wall 28 ofthe groove H. The sealing member 18 is constructed as before but theretaining means 23 is in the form of an endless strip or band 29composed of metal or like relatively rigid material (by comparison withthe material of the sealing member I8). With this arrangement the partsare assembled by fitting the sealing member l8 into the band 29, puttingthese parts in positionupon the shaft l2 and finally screwing the collar21 into place. The band 29 can be split at one point in its length sothat it can be sprung open for assembly purposes and in this case thepacking device can be used with the form of groove l1 shown in Figures 1and 2, the resilience of the band 29 holding the sealing member l8firmly in position. Y

, Another, arrangement shown in Figure 4 is, adapted primarily forpreventing leakage of pressure fluid in the direction indicated by'thearascaies row 38. In this instance the sealing member i8 is ofsubstantially L-shaped radial section, one limb 3i constituting a tubeof short axial length compared with its diameter, said tube beingclamped against the bottom 22 of the groove l? by means of a retainingmember 23 comprising a helix of square seotionwire, the turns of saidhelix being indicated at 32. The other limb of the L section forms aradial flange 33 which is arranged to bear resiliently against thesurface of the bore ii in the member it and against the bottom 22 of thegroove ll. so as to form the requisite seal, aided, of course, by thefluid pres sure acting in the space is, as before.

Where the retaining means 23 comprises a number of turns of wire, thesemay be secured to gether by sweating, soldering, cementing or the like,or alternatively they may be held together at intervals by thin metalstrips, as indicated at a l in r gure 5, these-strips being initiallyU-shaped and having their ends 35 bent downwards over the wire turns 26after the latter have been a;oplied around the sealing member i It maybe desirable in some cases to it the packing device internally within agroove li'c formed'in the bore ii of the member iii, as indicatedgenerally at 33 in Figure 6, the shaft 12 in this instance, of course,having a plain cylindrical external surface. The construction of theparts is the same as before except that the limbs 20 and ill (or 33) aredirected inwards so as to engage resiliently with the surface of theshaft 32. As the retaining means 23 has, of course, to Press the sealingmember iil'outwards instead of inwards, it normally acts undercompression and it is therefore desirable that it should have sufficientrigidity to prevent buckling; for this reason it is preferred that theretaining means should talre the form of a band, such as 29 in Figure 3,although' a wire helix can be used so long as the wire is relativelystout.

It will be appreciated that the constructions which have been describedare given merely as examples and that various further modifications maybe made in the form and design of the sealing ring so as to suitrequirements What I claim is:

1. A packing device forpreventing leakage of fluid in an axial directionbetween a pair of merebers which move angularly one within the other,said packing device comprising an annular sesi- 'ing member of softresilient material such as rub-= ber and having a portion lying in thebase of a circumferential groove formed in one of the rela= tivelymovable members which portion is spaced from the surface of the other ofthe relatively movable members, and at least one annular portion free tobear on the surface of said other member, and retaining means forclamping the sealing member in a radial direction into firm engagementwith the bottom of the circumferential groove, said retaining meanslying within the confines of the circumferential groove andsubstantially filling the space between the first-mentioned portion ofthe sealing member and the other of the relatively rotatable members,where by the annular portion of the sealing member is supported on bothsides substantially up to the bearing surface of the latter.

2. In a seal construction, the combination with a pair of nestedrelatively movable'elements with one of said elements being providedwith a groove defined by spaced confronting faces and an intermediateface opposing the other element: of a resilient member disposed in saidgroove and havin; opposite faces with one of the opposite faces lyingflat against said intermediate face and the other opposite face disposedin spaced relation with said other element, said member being formedwith at least'one side wall spaced from the adjacent confronting face toprovide a channel for receiving fluid under sufiicient pressure forcompressing said side wall and elect extension thereof towards and intosealing enzasement a,sea,1as 3 FREDERICK SYDNEY

